scholarly journals LIQUID LIGHT FILTER FOR THE VISIBLE SPECTRUM BASED ON HYDROPHILIC SOLUTIONS

2021 ◽  
Vol 6 ◽  
pp. 225-229
Author(s):  
Konstantin S. Nikitin ◽  
Victor S. Efremov
Keyword(s):  
Light Transmission ◽  
Visible Spectrum ◽  
Light Filter ◽  
Principal Possibility

The principal possibility of designing a liquid light filter using hydrophilic solutions is considered. Search for hydrophilic solutions with the most uniform light transmission at all wavelengths of the visible spectrum.

FDTD Simulation of Light Propagation Inside a-Si:H Structures

2010 ◽  
Vol 1245 ◽  
Author(s):  
Alessandro Fantoni ◽  
Pedro Pinho
Keyword(s):  
Light Absorption ◽  
Electromagnetic Waves ◽  
Light Propagation ◽  
Light Transmission ◽  
Visible Spectrum ◽  
Propagation Model ◽  
Interface Roughness ◽  
Fdtd Simulation ◽  
Doping Density ◽  
Surface And Interface

AbstractWe have developed a computer program based on the Finite Difference Time Domain (FDTD) algorithm able to simulate the propagation of electromagnetic waves with wavelengths in the range of the visible spectrum within a-Si:H p-i-n structures. Understanding of light transmission, reflection and propagation inside semiconductor structures is crucial for development of photovoltaic devices. Permitting 1D analysis of light propagation over time evolution, our software produces results in well agreement with experimental values of the absorption coefficient. It shows the light absorption process together with light reflection effects at the incident surface as well as at the semiconductor interfaces. While the effects of surface reflections are easily taken into account by the algorithm, light absorption represents a more critical point, because of its non-linear dependence from conductivity. Doping density, density of states and photoconductivity calculation are therefore crucial parameters for a correct description of the light absorption-transmission phenomena through a light propagation model.The results presented in this paper demonstrate that is possible to describe the effect of the light-semiconductor interaction through the application of the FDTD model to a a-Si:H solar cell. A more general application of the model to 2D geometries will permit the analysis of the influence of surface and interface roughness on the device photovoltaic efficiency.

scholarly journals Harvesting Solar Energy from Asphalt Pavement

2021 ◽  
Vol 13 (22) ◽  
pp. 12807
Author(s):  
Md Fahim Tanvir Hossain ◽  
Samer Dessouky ◽  
Ayetullah B. Biten ◽  
Arturo Montoya ◽  
Daniel Fernandez
Keyword(s):  
Solar Energy ◽  
Energy Harvester ◽  
Light Transmission ◽  
Low Cost ◽  
Visible Spectrum ◽  
Weather Conditions ◽  
Element Analysis ◽  
Energy Harvesters ◽  
Wide Range ◽  
Self Powered

This study aims at designing and developing a new technique to harvest solar energy from asphalt pavements. The proposed energy harvester system consists of a pavement solar box with a transparent polycarbonate sample and a thin-film solar panel. This device mechanism can store energy in a battery charged over daytime and later convert it into electric power as per demand. A wide range of polycarbonate samples containing different thicknesses, elastic moduli, and light transmission properties were tested to select the most efficient materials for the energy harvester system. Transmittance Spectroscopy was conducted to determine the percent light transmission property of the polycarbonate samples at different wavelengths in the visible spectrum. Finite Element Analysis modeling of the pavement–tire load system was conducted to design the optimal energy harvester system under static load. It was followed by the collection of data on the generated power under different weather conditions. The energy harvesters were also subjected to vehicular loads in the field. The results suggest that the proposed pavement solar box can generate an average of 23.7 watts per square meter continuously over 6 h a day under sunny conditions for the weather circumstances encountered in South Texas while providing a slightly smaller power output in other weather circumstances. It is a promising self-powered and low-cost installation technique that can be implemented at pedestrian crossings and intersections to alert distracted drivers at the time of pedestrian crossing, which is likely to improve pedestrian safety.

Structure and Selected Properties of Intraocular Implants (PMMA, Acrylic)

2019 ◽  
Vol 56 (3) ◽  
pp. 621-624
Author(s):  
Marcin Gacek ◽  
Jerzy Wyslocki ◽  
Joanna Gondro ◽  
Franciszek Badura ◽  
Slawomir Letkiewicz
Keyword(s):  
Uv Radiation ◽  
Light Transmission ◽  
Visible Spectrum ◽  
Amorphous Structure ◽  
Intraocular Lenses ◽  
Light Spectrum ◽  
Implant Surgery ◽  
Clear Vision ◽  
Implant Coating ◽  
A Minor

This paper presents the results of an investigation into the structure and properties of intraocular lenses (IOL) that are available on the ophthalmological market. The majority of implants of this type are based on acrylics or poly(methyl methacrylate) (PMMA). The acrylic lenses can be curled, which allows the making of just a minor incision during the associated implant surgery. The drawback of PMMA implants is their high rigidity, resulting in the need for a larger incision during the implant surgery. The benefits accrued from wearing such an implant are (1) the correction of focus for clear vision and (2) protection of the retina against UV-A radiation. X-ray diffractometry has confirmed the amorphous structure of all of the lenses investigated in this paper. The absorption and transmittance of the selected implants have been measured; differences found in the directional values of the transmittance and absorbance suggest the presence of differences in the implant coating (such as: different thickness or lack of coating on one side). It has been found that the PMMA-based implants exhibit the better properties with a level of light transmission in the visible spectrum of almost 40% and total protection against UV radiation. The acrylic implants feature lower transmittance in the visible light spectrum, and two of the investigated acrylic lenses failed to provide adequate protection against the UV radiation.

Refractive index matching for high light transmission composite systems

2018 ◽  
Vol 52 (24) ◽  
pp. 3299-3307 ◽  
Author(s):  
Erin Keaney ◽  
John Shearer ◽  
Artee Panwar ◽  
Joey Mead
Keyword(s):  
Refractive Index ◽  
Light Transmission ◽  
Polymer System ◽  
Visible Spectrum ◽  
Optical Polymer ◽  
Index Matching ◽  
Dispersion Data ◽  
Refractive Index Matching ◽  
Transparent Composite ◽  
Index Match

Transparent optical polymer/filler systems can be produced into complex shapes for a range of applications, such as lenses, shields, and containers. This work used refractive index liquids as a model for polymer matrices to investigate the degree of refractive index match required to maintain high transmission in an inorganic-filled polymer system (cubic calcium fluoride with particle size of 1 to 5 µm) over the visible spectrum. It was determined that in order to achieve a transparent composite (>85% transmission with 10 mm pathlength) with this filler (using literature reported dispersion data), the materials must have a refractive index match within ±0.007 for 1.6 vol.% loading. With a loading of 3.1 vol.%, the matching range required was reduced to approximately ±0.002.

Two-Dimensional Microfluidic Photomasking for Microarray Patterning

2005 ◽  
Author(s):  
Jonathan McKechnie ◽  
David A. Sinton
Keyword(s):  
Visible Light ◽  
Small Area ◽  
Light Transmission ◽  
Visible Spectrum ◽  
Two Dimensional ◽  
Proof Of Concept ◽  
Dye Probe

This paper presents a novel microfluidic photomasking strategy. Two opaque, dyed streams hydrodynamically focus a transparent stream to define a line of light transmission. Aligning two separate chips orthogonal to each other defines a small area where the transparent streams overlap. A proof-of-concept chip was developed and tested using visible-spectrum light and a visible light absorbing dye. Probe spot sizes of ~80μm are attainable, with spacing between spots of ~150μm.

Nano-finishing of MEMS-based platforms for optimum optical sensing

2019 ◽  
Vol 3 (1) ◽  
pp. 39-53
Author(s):  
Ankur Gupta ◽  
Poonam Sundriyal ◽  
Aviru Basu ◽  
Kapil Manoharan ◽  
Rishi Kant ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Refractive Index ◽  
Surface Finish ◽  
Microelectromechanical Systems ◽  
Transmission Loss ◽  
Light Transmission ◽  
Visible Spectrum ◽  
Grazing Incidence ◽  
Wet Etching ◽  
Etching Technique

The surface finish of the microelectromechanical systems substrate, particularly the ones that are deployed in chip-based optofluidic systems, is of utmost importance, and the overall surface finish helps in preventing light scattering and associated losses. The proposed system is made up of a microchannel with a coating on its interior which acts as a cladding layer and possesses an air-like refractive index. The water-based solutions with refractive indices higher than the coating, when confined within such channels, act as waveguides with a refractive index difference which would allow grazing incidence at the solution film interface. The microchannel is fabricated over a piece of Si along <100> direction with the help of lithography and wet etching technique. After wet chemical etching of silicon, multiple pyramidal hillocks with overall large surface roughness is observed which are not appropriate for loss-free light transmission and cause various optical losses. So the overall optimization of surface roughness created by the etching processes is critical from an optical standpoint. Roughness in the microchannel surface mainly arises due to wet etching through tetra methyl alcohol, potassium hydroxide, potassium ferricyanide and isopropyl alcohol. In this work, we have obtained surface finish upto ~1.33 nm at an etch rate of 141 nm/min which is obtained by tweaking the composition of the participating reagents in the etchants and also the etching temperature. The surface roughness obtained is quite small in comparison to the wavelength range of the visible spectrum and thus losses were greatly avoided. The low refractive index films over silicon substrate were characterized by field emission scanning electron microscopy, energy dispersive analysis of X-ray, atomic force microscopy, 3D optical profilometry and ellipsometry. The transmission results show that transmission loss was reduced by 27.42% for the coated samples with 33 nm surface roughness as compared to surface with 250 nm roughness.

Broadband asymmetric light transmission based on all-dielectric metasurfaces in the visible spectrum

2019 ◽  
Vol 21 (5) ◽  
pp. 055104 ◽  
Author(s):  
Ahmet Ozer ◽  
Nazmi Yilmaz ◽  
Hasan Kocer ◽  
Hamza Kurt
Keyword(s):  
Light Transmission ◽  
Visible Spectrum

Advanced TEM sample preparation techniques for submicron Si devices

1995 ◽  
Vol 53 ◽  
pp. 516-517 ◽  
Author(s):  
P. B. Basham ◽  
H. L. Tsai
Keyword(s):  
Sample Preparation ◽  
Process Development ◽  
Light Transmission ◽  
Specific Area ◽  
Turnaround Time ◽  
Small Hole ◽  
Area Of Interest ◽  
Transmission Electron ◽  
Polished Side ◽  
Preparation Techniques

The use of transmission electron microscopy (TEM) to support process development of advanced microelectronic devices is often challenged by a large amount of samples submitted from wafer fabrication areas and specific-spot analysis. Improving the TEM sample preparation techniques for a fast turnaround time is critical in order to provide a timely support for customers and improve the utilization of TEM. For the specific-area sample preparation, a technique which can be easily prepared with the least amount of effort is preferred. For these reasons, we have developed several techniques which have greatly facilitated the TEM sample preparation.For specific-area analysis, the use of a copper grid with a small hole is found to be very useful. With this small-hole grid technique, TEM sample preparation can be proceeded by well-established conventional methods. The sample is first polished to the area of interest, which is then carefully positioned inside the hole. This polished side is placed against the grid by epoxy Fig. 1 is an optical image of a TEM cross-section after dimpling to light transmission.

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